Vertebral implant containment device and methods of use

ABSTRACT

A containment device is inserted between vertebral members in a patient and provides a rapid implant solution adapted for use in different applications. The device includes an interior volume to contain a curable substance at substantially atmospheric pressure. Upon filling the enclosure member with a curable substance, the enclosure member is able to conform to and maintain a space between vertebral members. The containment device may include an enclosure member constructed of an impermeable material adapted to constrain migration of the curable substance. The enclosure member may include an exterior wall surrounding the interior volume and an opening in the exterior wall that exposes the interior volume. The containment device may include end members that may be distracted to establish a desired vertebral spacing. Spacer members may be included to further maintain the desired spacing. Upon hardening of the curable substance, the device is capable of maintaining the desired spacing.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/610,520, filed on Dec. 14, 2006, and incorporated in its entiretyherein by reference.

BACKGROUND

Spinal implants are often used in the surgical treatment of spinaldisorders such as degenerative disc disease, tumors, disc herniations,scoliosis or other curvature abnormalities, and fractures. Manydifferent types of treatments are used, including the removal of one ormore vertebral bodies and/or intervertebral disc tissue. In some cases,spinal fusion is indicated to inhibit relative motion between vertebralbodies. In other cases, dynamic implants are used to preserve motionbetween vertebral bodies. In yet other cases, relatively static implantsthat exhibit some degree of flexibility may be inserted betweenvertebral bodies. Regardless of the type of treatment and the type ofimplant used, surgical implantation tends to be difficult for severalreasons. For instance, access to the affected area may be limited byother anatomy. Further, a surgeon must be mindful of the spinal cord andneighboring nerve system.

In some applications, surgeons may wish to use a curing substance inlieu of more expensive and complex devices as a rapid vertebral bodyreplacement. Unfortunately, these curing substances tend to be fluid ormalleable in nature prior to curing and consequently tend to migrate inthe absence of a containment device. Accordingly, a containment devicemay be appropriate for use in these applications to control themigration of curable substances prior to hardening.

SUMMARY

Illustrative embodiments disclosed herein are directed to a containmentdevice that is insertable between vertebral members in a patient. Thecontainment device may provide a rapid, cost-effective implant solutionadapted for use in different applications.

The device may includes first and second end members each including afirst side and an opposing second side. The device may also include anenclosure member that extends around and is attached to each of thefirst and second end members and forms an interior volume between theend members. The first end member may be attached to the enclosuremember at a first location and the second end member may be attached tothe enclosure member at a second location that is spaced apart from thefirst location. The second sides of the first and second end members mayface into the interior volume. The first and second end members may bepositioned within the enclosure member and may be spaced from thevertebral members by the enclosure member when the containment device isinserted between the vertebral members. The enclosure member may bepositionable between a first orientation with the first and second endmembers in closer proximity and the interior volume being smaller, and asecond orientation with the first and second end members spaced afarther distance apart and the interior volume being larger. The firstand second end members may each be attached to the enclosure member andmove apart when the enclosure member moves from the first orientation tothe second orientation.

The device may include first and second end members each including afirst side and an opposing second side. An enclosure member may extendaround each of the first and second end members and form an enclosedinterior volume between the end members. Engagement features may bepositioned on the second sides of the first and second end members andmay be configured to receive a tool. The engagement features may besurrounded by the enclosure member and exposed in the interior volume.An opening in the enclosure member may extends into the interior volumeand may be positioned between the first and second end members and inproximity to the engagement features. The enclosure member may bepositionable between a first orientation with the engagement features ofthe first and second end members in closer proximity and the interiorvolume being smaller, and a second orientation with the engagementfeatures of the first and second end members spaced a farther distanceapart and the interior volume being larger.

The device may include first and second end members each including afirst side configured to contact one of the vertebral members and anopposing second side. An anchor recess may extend into the second sideof the first end member. The anchor recess may include a narrow inlet atthe second side that leads into an enlarged section positioned away fromthe second side. A flexible enclosure member may be attached to thesecond sides of each of the first and second end members and may form anenclosed interior volume between the end members. The enclosure membermay be positionable between a first orientation with the first andsecond end members in closer proximity and the interior volume beingsmaller, and a second orientation with the first and second end membersspaced a farther distance apart and the interior volume being larger.The enclosure member may be positioned away from the enlarged section ofthe anchor recess in the first orientation and positioned within theenlarged section of the anchor recess in the second orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a containment device according to oneembodiment;

FIG. 2 is a side elevation view of an unfilled containment deviceaccording to one embodiment positioned between vertebral bodies;

FIG. 3 is a side elevation view of a containment device according to oneembodiment positioned between vertebral bodies and being filled;

FIG. 4 is a side view of a containment device including end membersaccording to one embodiment;

FIG. 5 is a side view of a containment device including end membersaccording to one embodiment;

FIGS. 6-8 illustrate a sequence of implantation steps to obtain adesired vertebral body spacing, each Figure depicting a lateral view ofa containment device according to one or more embodiments shown relativeto vertebral bodies;

FIG. 9 is a side section view of a containment device including endmembers and spacer members according to one embodiment;

FIGS. 10-12 illustrate a sequence of implantation steps to obtain adesired vertebral body spacing, each Figure depicting a lateral view ofa containment device according to one or more embodiments shown relativeto vertebral bodies;

FIG. 13 is a side view of a containment device including end membersaccording to one embodiment; and

FIG. 14 is a side view of a containment device including end membersaccording to one embodiment.

DETAILED DESCRIPTION

The various embodiments disclosed herein are directed to vertebralimplants that include a containment device within which a curablesubstance may be inserted. The containment device is generally aflexible, collapsible member that includes an interior volume that maycontain the curable substance. The containment device may assume acompressed first state during installation of the containment device andmay be filled with a curable liquid substance to assume a second filledstate once the device is positioned within the body. An exemplarycontainment device 10 for supporting vertebral bodies is illustrated inFIG. 1. In one embodiment, the containment device 10 is a discectomy,vertebrectomy, or corpectomy implant positioned within an intervertebralspace. The intervertebral space may span a single disc space or may spanone or more vertebral levels along the longitudinal axis of the spinalcolumn. For example, FIGS. 2 and 3 illustrate that the containmentdevice 10 is positionable within an intervertebral space S to span oneor more vertebral levels along the longitudinal axis of the spinalcolumn. Although the illustrated embodiment of the implant 10 spans onevertebral level, it should be understood that the implant 10 may beconfigured to span multiple vertebral levels, including two or morevertebral levels.

In the illustrated embodiment, the containment device 10 includes aflexible enclosure member 12 that is constructed of a compliantbiocompatible material, such as a resin or polymer that may includematerials such as nylon, polyethylene, polyurethane, silicone,polyethylene, polypropylene, polyimide, polyamide, andpolyetheretherketone (PEEK). The enclosure member 12 may be formed frommaterials that are used in other conventionally known biomedicalapplications, such as balloon angioplasty. Further, the enclosure member12 may be reinforced with concentric layers of similar or dissimilarmaterials and/or fabrics (not specifically shown). For instance, areinforcing structure may be constructed of a wide variety of woven ornonwoven fibers, fabrics, metal mesh such as woven or braided wires,polymeric fibers, ceramic fibers, and carbon fibers. Biocompatiblefabrics or sheet material such as ePTFE and Dacron®, Spectra®, and/orKevlar® brand materials may also be used. In general, the enclosuremember 12 should be substantially impermeable with regards to a curablesubstance so that the curable substance remains confined to thecontainment device 10 and does not migrate to the patient by anexcessive amount. That is, the enclosure member 12 may be entirelyimpermeable such that all of the curable substance remains within theenclosure member 12. Alternatively, as with woven fabrics, the enclosuremember 12 may be slightly permeable such that some of the curablesubstance escapes the enclosure member without negative effect to thepatient. As used herein, the term “impermeable” is intended to covereach of these variations (e.g., entirely or substantially impermeable).

The enclosure member 12 includes longitudinal ends 14, 16 that arepositioned to engage vertebral members in use. The enclosure member 12includes a lateral wall 15 extending between the longitudinal ends 14,16. Further, the enclosure member 12 includes an opening 18 in thelateral wall 15 extending between the outside of the enclosure member 12and an interior volume 20 that is formed between the ends 14, 16 andwall 15. The opening 18 is not necessarily a sealed opening capable ofcontaining a curable substance at elevated pressures. Instead, theopening 18 provides access to the interior volume 20 to permit theenclosure member 12 to contain a curable substance at atmosphericpressure. Further, with the opening 18 facing upwards during surgery,the curable substance may be contained within the enclosure member 12 bygravity. Consequently, upon filling the enclosure member 12 with acurable substance, the enclosure member 12 is able to conform to a spacewithin which the enclosure member 12 is confined. Then, upon hardeningof the curable substance, the enclosure member 12 is capable ofmaintaining the inter-vertebral space and sustaining biomechanicalloading.

For example, the enclosure member 12 is adapted to engage the endplatesof upper and lower vertebral bodies V1, V2 as shown in FIGS. 2 and 3.The enclosure member 12 maintains an intervertebral axial space Sbetween the upper and lower vertebral bodies V1, V2 following theremoval of one or more vertebral levels (shown in phantom in FIGS. 2 and3). To facilitate insertion of the containment device 10, the enclosuremember 12 may be collapsed relative to a filled state as shown in FIG.2. The enclosure member 12 is compressed to fit between the vertebralbodies V1, V2, which are spaced apart a distance H. The opening 18 intothe interior volume 20 is laterally accessible in this state. Once thecontainment device 10 is positioned as shown in FIG. 2, an insertioninstrument 100 is used to introduce a curable substance 90 through theopening 18 and into the interior volume 20 of the enclosure member 12 asshown in FIG. 3.

The insertion instrument 100 may be implemented as a syringe-likestructure including a reservoir portion 102 and a delivery portion 104.The delivery portion 104 is configured to pass through the opening 18 totransfer the injectable substance from the reservoir portion 102 intothe interior volume 20 of the enclosure member 12. Other deliverymechanisms are certainly appropriate. For instance, pneumatic orhydraulic delivery systems may be appropriate. In other implementations,the curable substance 90 may include a malleable form, such as athickened paste, or clay-like consistency. Accordingly, the insertioninstrument 100 may comprise a scoop, blade, or other delivery instrumentfor inserting the curable substance 90. In other embodiments, thecurable substance 90 may be inserted manually (e.g., by hand) into theenclosure member 12. For more fluid curable substances 90, the deliveryportion 104 may be implemented as a needle, as tubing, or othercannulated devices. In any event, as the injectable substance isintroduced into the enclosure member 12, longitudinal ends 14, 16 areforced apart due to the expansion of the enclosure member 12.Ultimately, the containment device 10 assumes a filled second state thatspans the vertebral gap H as shown in FIG. 3. Notably, the vertebral gapH is substantially the same before and after filling the interior volume20 of the enclosure member 12, suggesting that the containment device 10is not intended to distract the vertebral bodies V1, V2. Instead, thecontainment device 10 is intended to fill the vertebral gap H using asimple device that confines a curable substance 90 to the space Sbetween the vertebral bodies V1, V2.

A variety of curable substances 90 may be inserted into the enclosuremember 12. In one embodiment, the curable substance fluid, liquid, gas,or solid (e.g., powder or granules) that hardens to a more rigid stateafter a predetermined amount of time or under the influence of anexternal catalyst. For instance, a curable substance 90 may cure underthe influence of heat or light, including ultraviolet light. Someexamples of in situ curable liquids include epoxy, PMMA, polyurethane,and silicone. The curable substance 90 may assume a first state 90during insertion and assume a second state 90A after insertion into theinterior volume 20 of the enclosure member 12. For example, the curablesubstance 90 in the first state may be fluid to facilitate insertion.Then, the curable substance 90A may cure to a substantially rigid stateor to a flexible, but relatively incompressible state.

In the illustrated embodiment, enclosure member 12 includes acylindrical shape, though other shapes may be used. In furtherembodiments, the enclosure member 12 may take on other types ofconfigurations, such as, for example, a circular shape, semi-oval shape,bean-shape, D-shape, elliptical-shape, egg-shape, or any other shapethat would occur to one of skill in the art. In other embodiments, theenclosure member 12 could also be described as being annular, U-shaped,C-shaped, V-shaped, horseshoe-shaped, semi-circular shaped, semi-ovalshaped, or other similar terms defining an implant including at least apartially open or hollow construction. Thus, the enclosure member 12 maybe constructed for use in a variety of procedures, including but notlimited to those requiring an anterior approach, a lateral approach, aposterior approach, or a trans-foraminal approach.

It should further be appreciated that the size and/or configuration ofthe enclosure member 12 may be specifically designed to accommodate aparticular region of the spinal column and/or a particular vertebrallevel. For example, in embodiments associated with the upper thoracic orcervical region of the spine, the enclosure member 12 may be designed tohave a D-shaped configuration, whereas embodiments associated with thelumbar region of the spine may be configured to have a cylindrical,horseshoe-shape, a U-shape, or other types of open-sided configurations.

In the embodiment shown in FIGS. 1-3, the containment device 10 includesprimarily an enclosure member 12 within which a curable substance 90 isinserted. Thus, substantially the entire containment device 10 isflexible and implant rigidity is derived from the curable substance 90.In FIG. 4, the containment device 10 includes a first end member 22, asecond end member 24, and an enclosure member 12 between the first andsecond end members 22, 24. The end members 22, 24 are adapted to engagethe endplates of upper and lower vertebral bodies V1, V2. In thisparticular embodiment, the enclosure member 12 is confined to the spacebetween the end members 22, 24 and does not directly contact thevertebral bodies V1, V2. In FIG. 5, the containment device 10 includesfirst 22 and second 24 end members that are contained within theinterior volume 20 of the enclosure member 12. Since the end members 22,24 are contained within the enclosure member in this particularembodiment, the enclosure member 12 contacts the vertebral bodies V1,V2. In one embodiment, the end members 22, 24 are formed of abiocompatible material, such as, for example, a carbon fiber material,or non-metallic substances, including polymers or copolymers made frommaterials such as PEEK and UHMWPE. In further embodiments, the endmembers 22, 24 may be formed of other suitable biocompatible materialsincluding metals, such as, for example, stainless steel, titanium,cobalt-chrome, or shape memory alloys. In one embodiment, the endmembers 22, 24 are coupled to the enclosure member 12. In oneembodiment, the end members 22, 24 are separable from the enclosuremember 12.

In the embodiment shown in FIG. 4, the end members 22, 24 directlycontact the vertebral bodies V1, V2. The bone contact surfaces 23, 25 ofthe end members 22, 24 may include surface geometry, coating, orporosity as are found in conventionally known vertebral implants.Surface features such as these are used to promote bone growth andadhesion at the interface between an implant and a vertebral end plate.Examples of features used for this purpose include, for example, teeth,scales, keels, knurls, and roughened surfaces. Some of these featuresmay be applied through post-processing techniques such as blasting,chemical etching, and coating, such as with hydroxyapatite. The boneinterface surfaces 23, 25 may also include growth-promoting additivessuch as bone graft, bone morphogenetic protein (BMP), allograft,autograft, and various types of cement, growth factors, andmineralization proteins. Alternatively, pores, cavities, or otherrecesses into which bone may grow may be incorporated via a moldingprocess. Other types of coatings or surface preparation may be used toimprove bone growth into or through the bone-contact surfaces 23, 25.

The end members 22, 24 for either embodiment (FIG. 4 or 5) include adistractor engagement feature 26. The distractor engagement feature 26is included in the various embodiments as a means of achieving a desiredvertebral spacing between vertebral bodies V1, V2 that is subsequentlymaintained by inserting the curable substance 90 into the interiorvolume 20 of the enclosure member 12 and allowing the curable substance90 to harden. FIGS. 6-8 depict exemplary process steps by which thecontainment device 10 of FIG. 5 may be implanted. These same processsteps may be followed to implant the containment device 10 of FIG. 4.

In FIG. 6, the containment device 10, including end members 22, 24, isinserted and positioned within an intervertebral space formed after theremoval of one or more vertebrae or discs. The containment device 10 ispositioned with the aid of a distractor 300 that engages the respectivedistractor engagement features 26 in the end members 22, 24. Theexemplary distractor 300 extends along a longitudinal axis L andgenerally includes a first distractor arm 302 and a second distractorarm 304. The first and second distractor arms 302, 304 are coupled toone another via a hinge mechanism 306 which provides for pivotalmovement between the distractor arms 302, 304 about the hinge mechanism306. As should be appreciated, an inward compression force exerted ontothe proximal portions 302 a, 304 a of the distractor arms in thedirection of arrows A will cause the distal end portions 302 b, 304 b tobe outwardly displaced in the direction of arrows B. Thus, distractionof the vertebral bodies V1, V2 is achieved along longitudinal axis X,which corresponds at least generally with the longitudinal axis of thespine and of the containment device 10.

In the illustrated embodiment, the distractor 300 includes a threadedrod 320 having a first end portion 320 a rotatably coupled with theproximal end portion 304 a of the distractor arm 304, and a second endportion 320 b engaged within a threaded aperture (not specificallyshown) extending through the proximal end portion 302 a of thedistractor arm 302. As should be appreciated, the position of rod 320may be adjusted relative to the distractor arm 302 by threading the rod320 with a rotary knob 312 to correspondingly control the amount ofdistraction provided by the distractor arms 302, 304. In one embodiment,the distractor 300 is provided with a gauge or stop member 310 that isadapted to limit outward displacement of the distal end portion 302 b,304 b, which in turn correspondingly limits that amount of distractionprovided by the distractor arms 302, 304. In this manner, overdistraction of the intervertebral space S is avoided.

The distal end of the distal end portions 302 b, 304 b include geometrythat engages the distractor engagement features 26 of the end members22, 24. Notably, FIGS. 6, 7, and 10 illustrate one particular type ofdistractor 300 that uses a threaded rod 320 to achieve a mechanicaladvantage and distract the vertebral bodies V1, V2 a desired amount.However, those skilled in the art will appreciate that different typesof distractors may be used, including but not limited to devicesincorporating pneumatic, hydraulic, electrical, or mechanicaldisplacement forces. However, it is generally contemplated that thedistractor (300 or otherwise) include engaging features with a size andshape that engages the distractor engagement features 26, yet providesaccess to the enclosure member 12 while the distractor 300 is engagedwith the distractor engagement features 26 as described herein.

With the distractor 300 engaged in the distractor engagement features 26as shown in FIG. 6, the rotary knob 312 may be rotated to force thedistal end portions 302 b, 304 b in the direction of arrows B. FIG. 7shows the proximal ends 302 a, 304 a in closer proximity to one another.Correspondingly, the distal ends 302 b, 304 b are spaced farther apartcompared to the position shown in FIG. 7. That is, the vertebral spacingH1 from FIG. 6 is increased to a greater distance H2 in FIG. 7. Once thedesired amount of distraction is achieved, an insertion instrument 100is used to introduce a curable substance 90 into the interior volume 20of the enclosure member 12 as shown in FIG. 7 or using other techniquesdescribed herein. Once the curable substance 90 is allowed to cure orharden, the distractor 300 is removed, leaving the containment device 10positioned to maintain the desired spacing H2 between vertebral bodiesV1, V2 as shown in FIG. 8.

FIG. 9 depicts a side section view of one embodiment of a containmentdevice 10 that includes spacer members 28. That is, the implant 10generally includes a first end member 22 and a second end member 24 asdescribed above, and one or more spacer members 28 coupled between thefirst and second end members 22, 24. The spacer members 28 are formed ofa biocompatible material that may be the same or different that the endmembers 22, 24. For example, the spacer members may include a materialthat is less or more flexible than that of the end members 22, 24. Inone embodiment, the spacer members 28 are sufficiently strong tomaintain a desired amount of vertebral distraction while a curablesubstance 90 is inserted into the interior volume 20 of the enclosuremember 12 and allowed to harden. Once the curable substance 90 hardens,the composite structure formed by the curable substance 90 and thespacer members 28 should be sufficient to maintain the desired vertebralspacing in the patient.

The spacer members 28 may be separate from the end members 22, 24. Tofacilitate insertion of the implant 10, the spacer member 28 may beinserted into a patient separately from the end members 22, 24. That is,the end members 22, 24 may be inserted during a first insertion step andthe spacer member 28 may be inserted during a second, subsequentinsertion step. Depending upon a surgeon's preferences, the spacermembers 28 may be inserted between the end members 22,24 at differenttimes of an implantation procedure. The process steps illustrated inFIGS. 10-12 show one exemplary method of inserting the spacer members28. In one implementation, the containment device 10 may be insertedinto the space S between vertebral bodies V1, V2 as shown in FIG. 6.Then, once a desired amount of distraction (spacing H2) is obtained, thespacers members 28 may be positioned between the end plates 22,24 asshown in FIG. 10. Once the one or more spacer members 28 are positionedas desired, the distractor 300 may be removed, leaving the spacermembers 28 to maintain the desired distraction. Next, an injectioninstrument 100 is used to introduce a curable substance 90 into theinterior volume 20 of the enclosure member 12 as shown in FIG. 11. Thecurable substance 90 is allowed to harden and the containment device 10maintains the desired spacing H2 between vertebral bodies V1, V2 asshown in FIG. 12. Notably, the distractor 300 has already been removedat this stage, thus providing easier access to the enclosure members 12and eliminating the need to maintain the desired distraction while thecurable substance 90 hardens. Thus, the spacer members 28 may improvethe ease with which the curable substance 90 is introduced to theenclosure member and reduce the overall the time required for theprocedure.

FIGS. 13 and 14 illustrate that the end members 22, 24 may includeanchor recesses 30 that improve the interface at each end member 22, 24.In FIG. 13, the end members 22, 24 are shown separated from theenclosure member 12. Each end member 22, 24 includes an anchor recess 30that is sized and positioned to allow the enclosure member 12 to expandtherein. Thus, as the enclosure member 12 is filled with the curablesubstance 90, the enclosure member 12 may expand or extend into theanchor recess 30. As the curable substance 90 hardens, the enclosuremember 12 may be secured to the end members 22, 24.

Similarly, FIG. 14 depicts an embodiment in which the end members 22, 24are contained within the enclosure member 12. In this particularembodiment, the end members 22, 24 include recesses that are sized andpositioned to allow the curable substance 90 to expand therein. Thus, asthe enclosure member 12 is filled with the curable substance 90, thecurable substance expands or extends into the anchor recesses 30. Then,the curable substance 90 hardens to a more rigid state that is securedto the end members 22, 24.

Spatially relative terms such as “under”, “below”, “lower”, “over”,“upper”, and the like, are used for ease of description to explain thepositioning of one element relative to a second element. These terms areintended to encompass different orientations of the device in additionto different orientations than those depicted in the figures. Further,terms such as “first”, “second”, and the like, are also used to describevarious elements, regions, sections, etc and are also not intended to belimiting. Like terms refer to like elements throughout the description.

As used herein, the terms “having”, “containing”, “including”,“comprising” and the like are open ended terms that indicate thepresence of stated elements or features, but do not preclude additionalelements or features. The articles “a”, “an” and “the” are intended toinclude the plural as well as the singular, unless the context clearlyindicates otherwise.

The present invention may be carried out in other specific ways thanthose herein set forth without departing from the scope and essentialcharacteristics of the invention. For instance, the embodimentsdisclosed herein have contemplated a single implant positioned betweenvertebral bodies V1, V2. In other embodiments, two or more smallerimplants may be inserted between the vertebral bodies V1, V2. Thepresent embodiments are, therefore, to be considered in all respects asillustrative and not restrictive, and all changes coming within themeaning and equivalency range of the appended claims are intended to beembraced therein.

1. A device for insertion between vertebral members in a patient, thedevice comprising: first and second end members each including a firstside and an opposing second side; an enclosure member that extendsaround and is attached to each of the first and second end members andforms an interior volume between the end members; the first end memberattached to the enclosure member at a first location and the second endmember attached to the enclosure member at a second location that isspaced apart from the first location, the second sides of the first andsecond end members facing into the interior volume; the first and secondend members positioned within the enclosure member and being spaced fromthe vertebral members by the enclosure member when the containmentdevice is inserted between the vertebral members; the enclosure memberpositionable between a first orientation with the first and second endmembers in closer proximity and the interior volume being smaller, and asecond orientation with the first and second end members spaced afarther distance apart and the interior volume being larger; theenclosure member attached to the first sides of the first and second endmembers; the first and second end members each being attached to theenclosure member and move apart when the enclosure member moves from thefirst orientation to the second orientation.
 2. The device of claim 1,wherein the enclosure member further includes an opening that extendsinto the interior volume, the opening is positioned between the firstand second end members.
 3. The device of claim 1, wherein the enclosuremember is constructed from a flexible, impermeable material.
 4. Thedevice of claim 3, wherein the enclosure member includes a reinforcingstructure that reinforces the flexible, impermeable material.
 5. Thedevice of claim 1, wherein the second sides of the first and second endmembers include recesses that extend away from the interior volume, therecesses including a narrow neck and a wide end section.
 6. The deviceof claim 1, further comprising at least one support member positioned inthe interior volume and within the enclosure member, the at least onesupport member including a first section attached to the first endmember and a second section attached to the second end member.
 7. Adevice for insertion between vertebral members in a patient, the devicecomprising: first and second end members each including a first side andan opposing second side; an enclosure member that extends around each ofthe first and second end members and forms an enclosed interior volumebetween the end members; engagement features positioned on the secondsides of the first and second end members and being configured toreceive a tool, the engagement features being surrounded by theenclosure member and exposed in the interior volume; an opening in theenclosure member that extends into the interior volume, the openingpositioned between the first and second end members and in proximity tothe engagement features; the enclosure member positionable between afirst orientation with the engagement features of the first and secondend members in closer proximity and the interior volume being smaller,and a second orientation with the engagement features of the first andsecond end members spaced a farther distance apart and the interiorvolume being larger; the enclosure member attached to the first sides ofthe first and second end members at positions away from the engagementfeatures.
 8. The device of claim 7, wherein the enclosure member isspaced away from the engagement features.
 9. The device of claim 7,wherein the first and second end members and the enclosure member have asubstantially cylindrical shape in the second orientation.
 10. Thedevice of claim 7, wherein the enclosure member is constructed from aflexible, impermeable material.
 11. The device of claim 7, furthercomprising at least one support member positioned in the interior volumeand within the enclosure member, the at least one support memberincluding a first section attached to the first end member and a secondsection attached to the second end member.
 12. The device of claim 7,wherein the engagement features each include a back wall opposite fromthe interior volume and sidewalls that extend between the back wall andthe second sides of the support members.
 13. A device for insertionbetween vertebral members in a patient, the device comprising: first andsecond end members each including a first side configured to contact oneof the vertebral members and an opposing second side; an anchor recessthat extends into the second side of the first end member, the anchorrecess including a narrow inlet at the second side that leads into anenlarged section positioned away from the second side; a flexibleenclosure member that is attached to the second sides of each of thefirst and second end members and forms an enclosed interior volumebetween the end members; the enclosure member positionable between afirst orientation with the first and second end members in closerproximity and the interior volume being smaller, and a secondorientation with the first and second end members spaced a fartherdistance apart and the interior volume being larger; the enclosuremember positioned away from the enlarged section of the anchor recess inthe first orientation and positioned within the enlarged section of theanchor recess in the second orientation.
 14. The device of claim 13,wherein the anchor recess in the first end member is a first anchorrecess and further comprising a second anchor recess in the second sideof the second end member, the enclosure member positioned within thesecond anchor recess in the second orientation.
 15. The device of claim14, wherein the enclosure member is positioned away from the first sidesof each of the first and second end members.
 16. The device of claim 13,wherein the recess extends into the second side of the first end membera distance less than a thickness of the first end member measuredbetween the first and second sides.
 17. The device of claim 13, whereinthe first and second end members are separated from the interior volumeby the enclosure member.